JPH0642440B2 - Capacitor with safety device - Google Patents

Description

The present invention relates to a capacitor with a safety device.

(Prior Art) When an overcurrent flows through the capacitor and abnormal heat is generated, the capacitor is destroyed and smokes or burns, damaging the device.

Conventionally, in order to prevent this accident, a current fuse or a temperature fuse is connected in series with a capacitor element, and an overcurrent or abnormal heat generation is detected to activate the fuse to interrupt the current flowing into the capacitor. .

(Problems to be Solved by the Invention) However, in a capacitor formed by winding a metallized film as an element, the film melts together with the metal layer due to abnormal heat generation. When the melt having the conductivity is generated near the end face, the melt may contact the terminal, and there is a drawback that the capacitor is not opened from the external circuit even when the fuse operates.

An object of the present invention is to improve the above-mentioned drawbacks and to provide a capacitor with a safety device that can be surely opened from an external circuit when a fuse operates.

(Means for Solving Problems) In order to achieve the above-mentioned object, the present invention forms a capacitor element by winding a metallized film, forms a metallikon on an end face of the capacitor element, and forms the metallikon and a terminal. In a capacitor with a safety device, in which a fuse is connected via a lead wire between the two, provide an insulating member that covers the end of the capacitor element together with the metallikon for a length of 4 mm or more, and a terminal arranged outside the insulating member. And a capacitor with a security device.

(Operation) According to the present invention, since the end portion of the capacitor element is covered with the insulating member, even if the film is melted, it can be prevented from coming into contact with the terminal.

(Example) Hereinafter, the present invention will be described based on illustrated examples.

In FIG. 1, reference numeral 1 is a rectangular resin case, a part of which is open. Reference numeral 2 denotes a capacitor element housed in the resin case 1, which is a flattened product obtained by laminating and winding metallized plastic films. 3 and 4
Is a metallikon formed on the end face of the capacitor element 2. Reference numeral 5 denotes a terminal connected to the metallikon 4, which is drawn out of the resin case 1. 6 is a capacitor element 2
Is an insulating member including an insulative cap whose end is covered with the metallikon 3, and a hole 8 is provided at the position of the core 7. A thermal fuse 10 is inserted in the core 7, and is housed in the holder 11. Thermal fuse 10
The lead wires 12 and 13 of the
4 and the latter is connected to the metallikon 3.
The terminal 14 is brought into contact with the outer surface of the insulating member 6 and is drawn out of the resin case 1. Reference numeral 15 is a resin filled in the resin case 1.

That is, according to the above-described embodiment, the insulating member 6 is provided at the end of the capacitor element 2 on the side where the thermal fuse 10 is connected, and even if an overcurrent flows and an abnormal temperature rise occurs, the metallized film near the end melts. However, this melt is
Is prevented from adhering to.

An insulating tape may be wrapped around the end of the capacitor element instead of the cap, and the end of the capacitor element of any size may be covered.

FIG. 2 shows another embodiment of the present invention, in which the temperature fuse 16 and the current fuse 17 are respectively provided in separate terminals 18.
And 19 and are arranged on the side surface of the capacitor element 20. Both end surfaces of the capacitor element 20 are covered with an insulating member 21 such as an insulating cap or insulating tape.

In the embodiment of FIG. 1, a capacitor having a length of 51 mm and a cap made of polypropylene, which has a rated voltage of 200 V and a rated capacity of 70 μF, is used.
With respect to the samples in which the coating length of the capacitor element end of the cap was changed, the safety function when an overcurrent was passed was measured, and the results are shown in the table. The number of samples is 50 each.

As is apparent from the table, when the length is 4 mm or more, the capacitor can be surely released from the circuit without coming into contact with the terminals even if the melted substance is generated.

(Effect of the Invention) As described above, according to the present invention, the end of the capacitor element on the fuse connection side is covered with an insulating member such as an insulating cap or insulating tape for a length of 4 mm or more, and the terminal is arranged on the opposite side. Therefore, the melt can be prevented from adhering to the terminals, and a highly reliable capacitor with a safety device that can ensure the fuse operation can be obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of another embodiment of the present invention. 2, 20 ... Capacitor element, 3, 4 ... Metallicon 5, 14, 18, 19 ... Terminal, 6, 21 ... Insulating member, 10, 16 ... Thermal fuse, 14 ... Terminal, 17 ... Current fuse.

Claims (1)

[Claims] 1. A metallized film is wound to form a capacitor element, and a metallikon is formed on an end surface of the capacitor element,
In a capacitor with a safety device, in which a fuse is connected between the metallikon and a terminal through the lead wire, an insulating member in which the end of the capacitor element is covered with the metallikon for a length of 4 mm or more, and a terminal arranged outside the insulating member A capacitor with a safety device, characterized by being provided with.